Black overprint
The Black overprint (for Pure Black) option specifies whether black text, or black text and vector graphics (where
black is defined as RGB=0, 0, 0, or as CMYK=0%, 0%, 0%, 100%) print over colored backgrounds. If you turn off this
option, black text, or black text and graphics knock out colored backgrounds. Knocking out can create a white edge
around objects, or a white space, caused by the misalignment of color plates.
Note: You can set Black overprint (for Pure Black) only if Black text and graphics is set to Pure Black On.
The Black overprint (for Pure Black) option has the following settings:
•
Text - Black text overprints colored backgrounds, eliminating white gaps and reducing the halo effect from
misregistration of colors.
•
Text/Graphics - Black text and graphics overprint colored backgrounds, eliminating white gaps and the halo
effect from misregistration of colors.
•
Off - Black text and graphics knock out colored backgrounds.
Note: PostScript applications may perform their own black overprint conversions before printing.
An example of how you might use this setting is a page that contains black text on a light blue background. The
background blue is CMYK=40%, 30%, 0%, 0%. The black text is CMYK=0%, 0%, 0%, 100%.
•
With Black overprint (for Pure Black) set to Text or Text/Graphics, the final text or graphic portions of the page
are overprinted, or combined with the underlying color. Black colors generated by applications (for example,
RGB=0, 0, 0 or CMYK=0%, 0%, 0%, 100%) are printed using black only. This means that black text and line art do
not exhibit halftone artifacts (as long as the printer is calibrated correctly). No transition in cyan and magenta
occurs and the quality of the output is improved, because it does not show artifacts near the edges of text.
•
With Black overprint (for Pure Black) set to Off, the border of the text or graphic is on an edge that has cyan and
magenta on one side (outside the object) and black on the other side (inside the object). This transition may
cause visible artifacts due to the practical limitations of the printer.
Note: The reproduction of CMYK components is affected by the CMYK Source setting and calibration when CMYK
is not 0%, 0%, 0%, 100%.
Black point compensation
The Black point compensation option lets you control the output quality of shadow areas for CMYK source colors.
Black point compensation works by scaling the source colors so that the darkest point in the source profile maps to
the darkest point in the output profile. Use Black point compensation to enhance details in shadows when the
CMYK source space is larger than the gamut of the printer. In proofing applications, when the CMYK source space
is smaller than the gamut of the printer, do not use this option.
Note: For RGB source colors, black point compensation is always applied to Relative Colorimetric. Black point
compensation does not apply to Absolute Colorimetric. Photographic already scales the saturated colors and shadow
detail to the color capabilities of the output device, so black point compensation is not relevant.
Color Printing
Color print options
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